Process of making battery-separators



UNITEDTSTATESA PATENT OFFICE.

HARRY S. STRONACH, OF OAK IARK, ILLINOIS, ASSIGNOR T0 ADDIE B. STBONACH, 0F

' OAK PARK, ILLINOIS.

Specification of Letters Patent.

i Patented Oct. 12, 1920.

Application led June 5, 1920. Serial No. 386,703.

To all whom t may concern Be it known that I, HARRY S. STnoNAoH, a citizen of the United States, residing at Oak Park, in the county of Cook, and State of Illinois, have invented certain new and useful Improvements in Processes of Making Battery-Separators, of which the following is a specification.

This invention relates to wooden separators for use in batteries.

As it is well known, hard rubber, celluloid, wood and glass are the materials generally used for making separators between plates of batteries.

Wood has been originally used and after many attempts to use other materials in preference to it, it was found to give better all around satisfaction than other materials and wood separators are now commonly used in all types of cells.

W'ooden separators of today are made out of ordinary lumber or veneer and no attempt has been made to utilize the natural structure of the pores of the Wood to the fullest extent.

It is applicants object to provide a wooden separator that utilizes the natural porosity of the wood to the fullest extent and in the same manner nature uses it in the natural growth of the tree, thereby providing a separator which oersan exceedingly small resistance to the circulation of the electrolyte solution and making it possible to produce batteries of small internal resistance.

It is another object to provide a wooden separator which is highly porous and yet mechanically strong.

In order to make a'wooden separator `oil. the highest porosity it is necessary to manufacture the same in a special manner giving particular attention to the natural porosity of the wood.

As the sap of the tree runs around and up and down through the soft porous summer growth or ring of the tree, the cells of this part of the tree are especially adapted by nature for this purpose.

It is another object of this invention to provide a wooden separator that utilizes the porosity as nature provides the same, to its fullest extent in each and every separator, thereby giving the greatest possible efflciency to the battery.

I .have found that Sheets cut from a block of red cedar with particular attention paid to utilizing the natural porosity of the wood make ideal separators.

For full understanding of the invention, reference is had to the accompanying drawings in which- Figure l shows the annular growth of a tree.

Fig. 2 shows a cross section of the tree showing the close hard winter growth or rings and also the soft porous summer growth or rings through which the sap flows around and up and downl the tree.

Fig. 3 shows a block of wood prepared for cutting into separator plates.

Fig. 4 shows a separator plate cut from a block such as shown in Fig. 3.

Fig. 5 shows a block of wood prepared in a slightly dierent way, and

Fig. 6 shows a separator cut from a block such as shown in Fig. 5.

The arrows marked A in Fig. 1, indicate the flow of the sap. As is well known, the trunk of a tree consists of a plurality of concentric substantially annular zones or layers of relatively soft or spongy wood and relatively thin intermediate layers of hard wood. These alternate layers of soft and hard wood represent the rapid summer growth and the slow winter growth respectively. The sap can readily flow through the spongy or porous texture of the summer growth both in up and down direction and circumferentially between the hard layers, but not through the hard layers.

- In Fig. 2 the hard rings are indicated by the numeral 1 and the intermediate zones of soft or spongy wood by the numeral 2.

It will readily appear that a plate of wood cut out of the position indicated by the letter Z in Fig. 2 will ofer a maximum 'of resistance to the flow of the electrolyte transversely of the plate just as the sap in nature encountered a maximum of resistance in radial direction through the hard ring forming a barrier.

Also a plate cut from the position indicated by the letter Y offers a high resistance to the flow of the electrolyte although the plate is partly cut across the rings. This' plate fairly indicates the Way separator plates are usually cut.

In contradistinction to these two ways of `cutting plates from a tree, I propose to cut the plates substantially as ,ndated by the position X. It is obvious that as the sap is free to flow'practically unrestrained ,up and down and transversely of the section indicated, so the electrolyte is free to circulate through the porous parts. The barrlers are at right angle tothe plane of the plate or substantiall so. This condition may be likened to enetian blinds in open position.

Fig. 3 shows a block of wood 3 prepared so that separator plates may be readily c ut from it, shaved, sliced, sawed or otherwise prepared, preferably in .the 'manner'. d escribed in m coending application Serlal Number 329, 66, led Oct. 10, 1919. As appears from Fig. 4, in a separatorplate cut from a block such as shown in Fig. 3, the grain runs substantially parallel with' the surface of the separator.

I have found that where the grain 1s more or less cross-cut as indicated in the block 4 shown in Fig. 5 and in the.separator out from it, as indicated in Fig. 6, the internal resistance is still smaller than in the separator shown in Fig. 4.

While separators made in this manner offer great advantages, whatever the kind of wood may be from which they are cut, I

' have found that red cedar is best suited and that it is more adapted than any other kind of wood', so far as I know, to carry out the object of the invention.

I claim:

l. A wooden separator cut from a block in 7. A block of wood prepared for cutting separator plates from it, in which the alternate layers of porous wood and hard wood extend substantially perpendicular to two side faces and to two end faces.

B. A block of wood prepared for cutting separator plates therefrom, in which the alternate layers of porous Wood and hard wood run transversely of the block and at a slight angle to the main faces thereof.

9. In a process of making wood separators the step which consists in cutting the wood across the rings indicating the annual growth.

10. In a process of making wood separators the step which consists in cutting the Wood substantially at right angle to the rings indicating the annual growth.

11. In a process of making wood separators the steps which consist in cutting from logs blocks in such a way that the alternate layers of porous wood and hard wood extend substantially perpendicularly to two side faces and to two end faces and then cutting plates from said block.

12. In a process of making wood separators the steps which consist in cutting from logs blocks in such a way that the alternate layers of porous wood and hard wood run transversely of the block and at a slight angle to the main faces thereof.

In testimony whereof I affix my signature.

HARRY s. sTRoNAcH. 

